CANCUN, Mexico -- There are several deadlocks still to be broken in the final 24 hours of U.N. climate talks, but one that matters most: the future of the Kyoto Protocol.

As negotiators from nearly 200 countries greeted Friday's dawn, still stuck on a range of issues, an impasse over whether Japan, Russia and Canada will commit to new emission targets after 2012 appears to be bringing the U.N. process to the edge of a cliff. If a compromise is not reached, negotiators and analysts said, carbon markets will falter and the quest for an even broader global climate treaty could be in ruins.

"If they don't get the [Kyoto Protocol], then everything crashes," said Albert Binger, science adviser to a group of small island nations.

"Today is a crucial day," said Brazilian negotiator Sergio Serra. "If we don't get an agreement today, I think it will be difficult. I can't say we will have failed, because some miracle may happen tomorrow."

The stalemate on Kyoto has been brewing for some time. But Japan brought the issue to a head on the first day of negotiations in this Yucatan peninsula resort town when it declared unequivocally that it would not submit new greenhouse gas emission targets under a second phase of the treaty in 2012.

By late Friday at least 20 leaders, including Mexican President Felipe Calderon, had tried to telephone Japanese Prime Minister Naoto Kan to implore him to soften his country's stance, Japanese media reported and a delegate from the country confirmed to ClimateWire. Kan reportedly was too busy to take calls, indicating his chief negotiator had full authority.

Nevertheless U.S. Deputy Special Envoy for Climate Change Jonathan Pershing as well as other negotiators and ministers said they remain optimistic that the final 24 hours of the 16th Conference of the Parties (COP) to the U.N. Framework Convention on Climate Change will bring an agreement.

"There's always a place for compromise. We just have to find it," Pershing said as he hurried off to a meeting.

Adrian Macey, former New Zealand lead negotiator who now is the vice chairman of the Kyoto Protocol part of the global talks, said despite the drama, climate talks are following a well-worn path.

"Right now they stand where they always stand at a COP. We're at the immediate post-crisis phase. It's only now that people are ready to compromise," he said, adding, "More people than not want to preserve the multilateral system."

Indeed, "compromise" has been the word of the day at this seaside megaresort where the talks are being held. And by Thursday afternoon with the arrival of more ministers and a growing sense that certain stalemates could only be broken by political leaders, the mañana pace of the two weeks-long talks have stepped up considerably.

Shuttle diplomacy on bicycles
Throughout the day ministers and delegates rushed back and forth between the luxury Moon Palace hotel and a nearby conference hall for press conferences, plenary sessions and working group meetings. The European Union's Climate Commissioner Connie Hedegaard pedaled swiftly across the sprawling hotel grounds on bicycles provided to participants on her way to delegation offices. And actress Daryl Hannah stopped by to implore U.S. Envoy Todd Stern to "get it done."

The environmental activist and star of "Blade Runner" and "Wall Street," who has been living off-grid in her Rocky Mountains home for the past 20 years, said she is frustrated by what she sees as the "poker game" of global climate talks.

"It's incredibly frustrating to see the lack of action," she said while waiting for a meeting with U.S. Envoy Todd Stern. Introduced to Environment Minister Jairam Ramesh, Hannah reacted quickly to Ramesh's comment that he hoped negotiators could soon put "to bed" a climate agreement. "Bring it to life," the actress implored.

But for all the hustle, the day ended close to where it began. Countries are close to agreements on a fund to help vulnerable countries adapt to climate change; technology development; and protecting tropical forests. But overriding issues between the United States and emerging powers -- particularly China -- remain unresolved.

On technology, countries are working to create hubs or networks -- possibly one on each continent -- that will help developing nations figure out how to employ low-carbon technology instead of fossil fuels and meet the costs to do so, said Jake Schmidt of the Natural Resources Defense Council. Protecting intellectual property rights remains a major issue for the United States and others, but Schmidt said he believes that will get kicked down the road to be dealt with another time.

"The only way you can deal with the IP issue is not to deal with it," Schmidt said, predicting either nonexistent or vague text on the issue.

On finance, the creation of a "green fund" turns on some bottom-line positions from the United States that the board be comprised at least half of donor nations and establishing the World Bank as trustee. Those talks have generated fierce resentment toward the United States, which delegates said has been resisting language that long-term funding for vulnerable countries be "new and additional" and pushing back on transparency provisions.

U.S.-China dispute may stymie others
Neither those issues nor others like protection of forests will get solved at all, though, until the United States and China work out their own dispute. That centers on how transparent developing countries' efforts at lowering emissions should be and whether they will allow international analysis of those efforts.

By late Thursday, Ramesh -- who earlier this week proposed a compromise that won wide support -- said a deal on transparency is in the works.

"It's not a theological issue. It's a matter of dotting the Is and crossing the Ts," he said.

The Kyoto Protocol, on the other hand, "that's more of a sticking point," Ramesh said.

As of Thursday night, Japan's director of international strategy in the Ministry of Environment said there has been no change to his country's opposition to the 1997 treaty that only requires industrialized nations to cut emissions. The treaty's first five-year phase ends in 2012. The treaty itself automatically continues on, but countries must decide whether or not to submit new emission targets.

Japan will not, and by Thursday evening it was looking increasingly likely that Russia would make a similar announcement. Developing nations also say they are worried about whether Canada will stick with Kyoto.

Ailun Yang of Greenpeace China said an impasse would leave countries with two choices: approve watered-down language that would keep the machinery of the UNFCCC moving along; or acknowledge that countries had failed to find an agreement.

Venezuelan Amb. Claudia Salerno said neither option is acceptable.

"We cannot go back to our countries on December 12 and we open the door to our homes and talk to our children and say we were not able to do anything because it was very difficult," she said. "My girls are waiting for me at home to do something for the world I brought them into."